Ball valves require lubricant or grease for operation. A grease fitting is installed in the outside of the valve and allows grease to be fed into and around the ball of the valve. A grease fitting has a small opening to a channel which connects to the ball and the valve seat, but the small opening and channel are typically closed to atmosphere with a small ball enclosed inside and lying flush with the small opening. To open the channel between the atmosphere and the valve internal components, the small ball must be moved out of the way; moving the ball requires pressure. Thus, typically the grease is injected through the grease fitting into the valve internals using a grease gun, which delivers the grease at a pressure sufficient to move the ball from the opening.
Grease fittings are prone to failure and must be replaced from time to time. Failures include leaking, seal damage which causes loss of pressure within the valve seat, construction problems, or the introduction of foreign debris. Replacement requires isolation of the valve, which potentially requires a shutdown of all or part of the process containing the valve resulting in lost production. The process of replacing the grease fitting contains hazards. Current practices to replace a grease fitting require the valve containing the grease fitting to be shut down, isolated, depressurized, and drained. The valve and the grease within can be under pressure. The depressurization process poses hazards to workers. Drainage can result in oil spills that cause environmental harm. The entire process can take time which results in additional lost production.
Therefore, a process by which grease fittings can be replaced without shutting down production and with minimal exposure risks would be beneficial.